/************************************************************************************ 
 * Copyright (c) 2008, Thomas Graavard
 * All rights reserved.
 *
 * Used under license by the terms and conditions specified by the Microsoft Public License (Ms-PL)
 * 
 * For more information, please go to http://xnatweener.codeplex.com/license
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Columbia University nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY COLUMBIA UNIVERSITY ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <copyright holder> BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * 
 * ===================================================================================
 * Author: Thomas Graavard
 * Incorporated into GoblinXNA by Nicolas Dedual (dedual@cs.columbia.edu)
 * 
 *************************************************************************************/

using System;
using System.Collections.Generic;
using System.Text;

namespace GoblinXNA.Helpers.XNATweener
{
    public class Elastic
    {
        public static float EaseIn(float t, float b, float c, float d)
        {
		    if (t==0) 
            {
                return b;
            }
            if ((t /= d) == 1) 
            {
                return b+c;
            }
            float p = d * .3f;
            float s = p / 4;
            return -(float)(c * Math.Pow(2, 10 * (t -= 1)) * Math.Sin((t * d - s) * (2 * Math.PI) / p)) + b;
        }

        public static float EaseOut(float t, float b, float c, float d)
        {
		    if (t==0) 
            {
                return b;
            }
            if ((t /= d) == 1) 
            {
                return b+c;
            }
            float p = d * .3f;
            float s = p / 4;
		    return (float)(c * Math.Pow(2,-10*t) * Math.Sin((t*d-s)*(2*Math.PI)/p ) + c + b);
	    }

        public static float EaseInOut(float t, float b, float c, float d)
        {
            if (t == 0)
            {
                return b;
            }
            if ((t /= d / 2) == 2)
            {
                return b + c;
            }
            float p = d * (.3f * 1.5f);
            float a = c;
            float s = p / 4;
            if (t < 1)
            {
                return -.5f * (float)(a * Math.Pow(2, 10 * (t -= 1)) * Math.Sin((t * d - s) * (2 * Math.PI) / p)) + b;
            }
		    return (float)(a * Math.Pow(2,-10*(t-=1)) * Math.Sin( (t*d-s)*(2*Math.PI)/p )*.5 + c + b);
	    }
    }
}
